*{
    padding: 0;
    margin: 0;
}
li{
    list-style: none;
}
a{
    text-decoration: none;
}
.fl{
    float: left;
}
.fr{
    float: right;
}
.w{
    width: 1240px;
    margin: 0 auto; 
}
.clearfix::after{
    content:"";
    clear:both;
    display:block;
}
button,input{
    border: 0;
    /* 去掉表单聚焦时的效果 */
    outline: none;
}
a{
    cursor: pointer;
}